A method for controlling a wind power installation having a rotor operated with variable speed and having rotor blades that are adjustable in their blade angle. The installation is controlled in a partial-load range by an open-loop operating-characteristic control, which uses an operating characteristic. The operating characteristic presets a relationship between the rotational speed and a generator state variable to be set that is a generator power or torque. A value of the generator state variable preset by the operating characteristic is set in dependence on a detected speed. The installation is controlled in a full-load range by a closed-loop pitch control, in which the rotational speed is controlled to a speed setpoint value by adjusting the blade angles. In a presettable range of the partial-load range and/or in a transitional range from the partial-load range to the full-load range, the installation is controlled by a speed-power control.

The present disclosure relates to a control system for a wind turbine comprising more controllers and where at least some of the controllers operate at different sample frequencies. The control system comprises at least two controller units, a first controller (10) for determining an operational value (OV) of a sub-system and a second controller (20) for the sub-system. The second controller operates at a higher sample frequency than the first controller. It is disclosed that a faster reaction to a received demand value (V1), received for controlling the sub-system, can be obtained by setting the operational value (OV) of the sub-system as the sum of an internal operational value (V5) and a difference value (V4).

A method of controlling a turbine of a floating wind turbine structure to reduce fatigue of its moorings comprises curtailing the turbine based on a pitching motion of the wind turbine structure and on a wind direction at the wind turbine structure relative to the orientation of moorings of the wind turbine structure. Optionally, the curtailment may be further based on the degree of displacement of the wind turbine structure from a reference location.

A method for controlling a wind power installation, wherein the wind power installation has a rotor with a plurality of rotor blades, the rotor blades are adjustable in their blade angle, each rotor blade is activatable individually, for the individual activation, in each case a total adjustment rate R.sub.of which indicates an intended speed of change of the respective blade angle is predetermined, a collective blade angle identical for all of the rotor blades is provided, a collective adjustment rate identical for all of the rotor blades describes an intended speed of change of the collective blade angle, an individual offset angle which indicates a value by which the blade angle is intended to deviate from the collective blade angle is predetermined for each rotor blade, an individual feed forward control adjustment rate which indicates an adjustment rate which is provided for reaching the offset angle is determined for each rotor blade from the individual offset angle, an individual offset deviation is determined for each rotor blade depending on a comparison of the individual offset angle and a detected blade angle of the rotor blade, and the total adjustment rate of each rotor blade is determined depending on the collective blade angle and/or the collective adjustment rate, the individual feed forward control adjustment rate, and the individual offset deviation.

A method, an apparatus, a device and a system for controlling an oscillation damping caused by a series compensation for a wind power plant are provided. The method includes: extracting, a first dynamic small signal from first relevant parameters causing power oscillation, inputting the first dynamic small signal to a PID controller, and feeding an output control parameter from the PID to a rotor voltage controller as a first feedforward term; obtaining, according to second relevant parameters causing sub-synchronous oscillation, a virtual voltage, and feeding into a rotor voltage controller as a second feedforward term; and extracting a third dynamic small signal from third relevant parameters causing the oscillation of a rotor current loop and then performing phase and amplitude compensations on the third dynamic small signal, and feeding the output of the POD controller into the given position of a rotor current controller as a third feedforward term.

The present invention relates to a control system for thrust-limiting of wind turbines, which wind turbine comprises at least one tower, which tower carries at least one nacelle which nacelle comprises a rotating shaft, which shaft is rotated by one or more blades, which blades at pitch regulated by a pitch control system. It is the object of the present invention to reduce mechanical load and stress of a wind turbine. A further object is to reduce the maximal load on tower of a wind turbine. The thrust-limiting control system performs control of the pitch angle, which thrust-limiting control system performs regulation of the pitch angle based on at least a first input from a wind estimator and a second input from a turbulence estimator. By thrust-limiting control, reduction in the maximum mechanical load on a tower, or maybe also a nacelle, can be achieved by a relatively high percentage of the load in a way where it has only very limited influence on the power production of the wind turbine.

Aspects of the present invention relate to a method for controlling an amount of power to be delivered from a wind turbine generator to a power grid during an abnormal power grid event, the method comprising the steps of detecting an abnormal power grid event; controlling an active current delivered to the power grid in response to a measured or determined total active current; and controlling a reactive current delivered to the power grid in response to a measured or determined total reactive current. Aspects of the present invention further relate to a computer program product for carrying out the method as well as a wind turbine generator being capable of carrying out embodiments of the invention.

The invention provides a wind turbine having a system for positioning the rotor in an azimuthal reference position Az.sub.ref and for maintaining it therein for a predetermined period of time, the wind turbine being arranged in test mode. Said rotor positioning system comprises a first controller (31) configured to generate a generator speed reference .sub.ref from the difference between the rotor azimuthal reference position Az.sub.ref and the rotor azimuthal measured position Az.sub.meas and a second controller (35) configured to generate a generator torque reference T.sub.ref from the difference between said generator speed reference .sub.ref and the generator speed measured .sub.meas.

An equivalent variable pitch differential control method and apparatus. The method includes: acquire a first control parameter and a second control parameter respectively by means of a static energy deviation PI control method; acquire an equivalent differential third control parameter using a dynamic energy deviation; and by taking a wind wheel measurement rotating speed and a wind wheel reference rotating speed as inputs, a proportion integration differentiation controller controls a wind generating set according to the first control parameter, the second control parameter, and the third control parameter, thereby making a wind wheel rotating speed follow the wind wheel reference rotating speed. A wind generating set is controlled in real time by combining first and second control parameters and an equivalent differential third control parameter to serve as parameter values of the proportion integration differentiation controller.

The present invention relates to a multirotor wind turbine comprising at least two rotor nacelle assemblies mounted to a support arrangement via respective yawing systems, and a toe angle control system for controlling the toe angles of the rotor nacelle assemblies with respect to the support arrangement; wherein the toe angle control system is configured to operate in a first mode in which the rotor nacelle assemblies are held at positive toe angles while the wind turbine is generating power in a main production mode; wherein the toe angle control system is further configured to monitor the operating mode of the wind turbine, and to switch to a second mode in which the yawing systems of the rotor nacelle assemblies are operated to reduce the toe angles of the rotor nacelle assemblies if an operating mode-based trigger condition has been met.